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Journal ArticleDOI

Advances in bacterial exopolysaccharides: from production to biotechnological applications

TL;DR: Limitations and constraints ofacterial EPS development are stressed and correlation of bacterial EPS properties with polymer applications is emphasized, along with current downstream strategies.
About: This article is published in Trends in Biotechnology.The article was published on 2011-08-01. It has received 616 citations till now.
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TL;DR: The infant microbiota, the mechanisms that drive its establishment and composition, and how microbial consortia may be molded by natural or artificial interventions are described and the relevance of key microbial players of the infant gut microbiota, in particular bifidobacteria, with respect to their role in health and disease are discussed.
Abstract: The human gut microbiota is engaged in multiple interactions affecting host health during the host's entire life span. Microbes colonize the neonatal gut immediately following birth. The establishment and interactive development of this early gut microbiota are believed to be (at least partially) driven and modulated by specific compounds present in human milk. It has been shown that certain genomes of infant gut commensals, in particular those of bifidobacterial species, are genetically adapted to utilize specific glycans of this human secretory fluid, thus representing a very intriguing example of host-microbe coevolution, where both partners are believed to benefit. In recent years, various metagenomic studies have tried to dissect the composition and functionality of the infant gut microbiome and to explore the distribution across the different ecological niches of the infant gut biogeography of the corresponding microbial consortia, including those corresponding to bacteria and viruses, in healthy and ill subjects. Such analyses have linked certain features of the microbiota/microbiome, such as reduced diversity or aberrant composition, to intestinal illnesses in infants or disease states that are manifested at later stages of life, including asthma, inflammatory bowel disease, and metabolic disorders. Thus, a growing number of studies have reported on how the early human gut microbiota composition/development may affect risk factors related to adult health conditions. This concept has fueled the development of strategies to shape the infant microbiota composition based on various functional food products. In this review, we describe the infant microbiota, the mechanisms that drive its establishment and composition, and how microbial consortia may be molded by natural or artificial interventions. Finally, we discuss the relevance of key microbial players of the infant gut microbiota, in particular bifidobacteria, with respect to their role in health and disease.

970 citations


Cites background from "Advances in bacterial exopolysaccha..."

  • ...EPSs are carbohydrate polymers present as an extracellular layer covering the surfaces of various Gram-positive microorganisms (402)....

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Journal ArticleDOI
TL;DR: Catastrophe of heavy metal pollution in environment is discussed in terms of remediation through bacterial Exopolysaccharide through polymer in wide range of bacterial cells and their EPS in diverse forms have been critically analyzed.

523 citations


Cites background from "Advances in bacterial exopolysaccha..."

  • ...However, gram negative bacteria are generally believed to follow either Wzx-Wzy dependent or ABC transporter dependent pathway [25] with some exceptions (Ex- Synthase-dependent pathway followed by Pseudomonas aeruginosa)....

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  • ...It begins with the entry of the substrate (any form of sugar) in bacterium, actively or passively, which is catabolized by periplasmic oxidation or intracellular phosphorylation [25]....

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Journal ArticleDOI
Junqiao Wang1, Shuzhen Hu1, Shaoping Nie1, Qiang Yu1, Mingyong Xie1 
TL;DR: This work summarized the latest discoveries and advancements in the study of antioxidative polysaccharides and gave a detailed description of the possible mechanisms of these antioxidant actions.
Abstract: It is widely acknowledged that the excessive reactive oxygen species (ROS) or reactive nitrogen species (RNS) induced oxidative stress will cause significant damage to cell structure and biomolecular function, directly or indirectly leading to a number of diseases The overproduction of ROS/RNS will be balanced by nonenzymatic antioxidants and antioxidant enzymes Polysaccharide or glycoconjugates derived from natural products are of considerable interest from the viewpoint of potent in vivo and in vitro antioxidant activities recently Particularly, with regard to the in vitro antioxidant systems, polysaccharides are considered as effective free radical scavenger, reducing agent, and ferrous chelator in most of the reports However, the underlying mechanisms of these antioxidant actions have not been illustrated systematically and sometimes controversial results appeared among various literatures To address this issue, we summarized the latest discoveries and advancements in the study of antioxidative polysaccharides and gave a detailed description of the possible mechanisms

484 citations

Journal ArticleDOI
TL;DR: A review of the progress made in recent years on nanoparticle biosynthesis by microbes is presented in this paper, which mainly focuses on the biosynthesis of the most commonly studied metal and metal salt nanoparticles such as silver, gold, platinum, palladium, copper, cadmium, titanium oxide, zinc oxide, and lead oxide.
Abstract: Metal nanoparticles have received great attention from researchers across the world because of a plethora of applications in agriculture and the biomedical field as antioxidants and antimicrobial compounds. Over the past few years, green nanotechnology has emerged as a significant approach for the synthesis and fabrication of metal nanoparticles. This green route employs various reducing and stabilizing agents from biological resources for the synthesis of nanoparticles. The present article aims to review the progress made in recent years on nanoparticle biosynthesis by microbes. These microbial resources include bacteria, fungi, yeast, algae and viruses. This review mainly focuses on the biosynthesis of the most commonly studied metal and metal salt nanoparticles such as silver, gold, platinum, palladium, copper, cadmium, titanium oxide, zinc oxide and cadmium sulphide. These nanoparticles can be used in pharmaceutical products as antimicrobial and anti-biofilm agents, targeted delivery of anticancer drugs, water electrolysis, waste water treatment, biosensors, biocatalysis, crop protection against pathogens, degradation of dyes etc. This review will discuss in detail various microbial modes of nanoparticles synthesis and the mechanism of their synthesis by various bioreducing agents such as enzymes, peptides, proteins, electron shuttle quinones and exopolysaccharides. A thorough understanding of the molecular mechanism of biosynthesis is the need of the hour to develop a technology for large scale production of bio-mediated nanoparticles. The present review also discusses the advantages of various microbial approaches in nanoparticles synthesis and lacuna involved in such processes. This review also highlights the recent milestones achieved on large scale production and future perspectives of nanoparticles.

383 citations

References
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Journal ArticleDOI
TL;DR: The key aspects of bacterial biopolymer production are summarized and how a better understanding of polymer biosynthesis and material properties can lead to increased use of bacterialBiopolymers as valuable renewable products are highlighted.
Abstract: Bacteria can synthesize a wide range of biopolymers that serve diverse biological functions and have material properties suitable for numerous industrial and medical applications. A better understanding of the fundamental processes involved in polymer biosynthesis and the regulation of these processes has created the foundation for metabolic- and protein-engineering approaches to improve economic-production efficiency and to produce tailor-made polymers with highly applicable material properties. Here, I summarize the key aspects of bacterial biopolymer production and highlight how a better understanding of polymer biosynthesis and material properties can lead to increased use of bacterial biopolymers as valuable renewable products.

706 citations

Journal Article
TL;DR: Bacterial cellulose, an exopolysaccharide produced by some bacteria, has unique structural and mechanical properties and is highly pure as compared to plant cellulose.
Abstract: Summary Bacterial cellulose, an exopolysaccharide produced by some bacteria, has unique structural and mechanical properties and is highly pure as compared to plant cellulose. This article presents a critical review of the available information on the bacterial cellulose with special emphasis on its fermentative production and applications. Information on the biosynthetic pathway of bacterial cellulose, enzymes and precursors involved in bacterial cellulose synthesis has been specified. Characteristics of bacterial cellulose with respect to its structure and physicochemical properties are discussed. Current and potential applications of bacterial cellulose in food, pharmaceutical and other industries are also presented.

540 citations

Journal ArticleDOI
TL;DR: The present article converges on bacterial exopolysaccharide, which are rich in high molecular weight polysaccharides and have heteropolymeric composition and have new‐fangled applications due to the unique properties they possess.
Abstract: Microbial polysaccharides are multifunctional and can be divided into intracellular polysaccharides, structural polysaccharides and extracellular polysaccharides or exopolysaccharides (EPS). Extracellular polymeric substances (EPS), produced by both prokaryotes (eubacteria and archaebacteria) and eukaryotes (phytoplankton, fungi, and algae), have been of topical research interest. Newer approaches are carried out today to replace the traditionally used plant gums by their bacterial counterparts. The bacterial exopolysaccharides represent a wide range of chemical structures, but have not yet acquired appreciable significance. Chemically, EPS are rich in high molecular weight polysaccharides (10 to 30 kDa) and have heteropolymeric composition. They have new-fangled applications due to the unique properties they possess. Owing to this, exopolysaccharides have found multifarious applications in the food, pharmaceutical and other industries. Hence, the present article converges on bacterial exopolysaccharides.

520 citations

Journal ArticleDOI
TL;DR: This review includes information on the structure, properties and molecular genetics of the bacterial (1→3)-β-glucans, together with an overview of the physiology and biotechnology of curdlan production and applications of this biopolymer and its derivatives.
Abstract: Three structural classes of (1-->3)-beta-D-glucans are encountered in some important soil-dwelling, plant-associated or human pathogenic bacteria. Linear (1-->3)-beta-glucans and side-chain-branched (1-->3,1-->2)-beta-glucans are major constituents of capsular materials, with roles in bacterial aggregation, virulence and carbohydrate storage. Cyclic (1-->3,1-->6)-beta-glucans are predominantly periplasmic, serving in osmotic adaptation. Curdlan, the linear (1-->3)-beta-glucan from Agrobacterium, has unique rheological and thermal gelling properties, with applications in the food industry and other sectors. This review includes information on the structure, properties and molecular genetics of the bacterial (1-->3)-beta-glucans, together with an overview of the physiology and biotechnology of curdlan production and applications of this biopolymer and its derivatives.

387 citations

Journal ArticleDOI
TL;DR: Three-dimensional encapsulation of NIH-3T3 fibroblast cells in MeGG networks demonstrated in vitro biocompatibility confirmed by high cell survival and the in vitro swelling kinetics and hydrolytic degradation rate were dependent on the crosslinking mechanisms used to form the hydrogels.

332 citations